The invention relates to a method of monitoring processes, in particular the printing process, in a web-processing printing machine. The invention relates in particular to a method according to which process variables are identified in a process space as operating values, which include at least the web tension and the web speed, a measurement of actual values of the operating values is carried out, a presetting or a measurement of actual values of at least one operating parameter that influences these operating values is performed and operating values are assessed as a function of the operating parameters.
It is generally known to measure individual process variables in a printing machine and also to evaluate them as a function of the process state. In the set of individual process variables for the case of a web-processing printing machine, particular significance is attached to the operating values of web tension and web speed. One source of risk for the nonproductivity of a printing machine for a printing material web is, in particular, a web break, which can frequently be attributed to an inappropriate web tension and/or web speed. The risk of the occurrence of such a situation is often only poorly known or can only be poorly estimated. Known monitoring devices for printing machines from time to time permit subsequent analysis of a problem situation but not its avoidance through the use of a prewarning or prediction of inappropriate operating values in the process space of the process variables.
An appropriate and user-friendly visualization of process states of a technical plant is often difficult, because of a multidimensional interdependence and is associated with a large computational outlay. For example, in Published European Patent Application No. EP 0 829 809 A1, a method for the multidimensional display of process states of a technical plant is disclosed, being suitable in particular for the display of process states in a power station plant. In order to permit simultaneous and coherent assessment and display of relevant process variables of the plant, it is proposed to evaluate the relevant process variables in a relationship with one another through the use of a neural analysis on the basis of self-organizing maps by a topology-maintaining, nonlinear projection of data of the relevant process variables onto a multidimensional neural map being implemented. Through the use of dynamic visualization of win rates of individual neurons, a projection of the physical plant states onto a developed map is carried out, so that through the use of a neural xe2x80x9cwinner takes allxe2x80x9d algorithm, the current winner neuron is determined and the summed winner rates of the individual neurons on the map can be displayed in encoded form. Through the use of the method described, each plant state which is determined by a plurality of independent process variables can be represented through the use of a projection onto only two or three dimensions, so that improved clarity relating to the actual process states is achieved. Therefore, according to the invention, a projection is carried out onto nonlinear surfaces, so-called main manifolds, which are covered by the topology-maintaining maps in the state space.
The disadvantage when applying such a method to the display of process states of a printing machine for a printing material web is, in particular, the high computational outlay. Furthermore, the process space can be broken down into operating values, to which an actual value and a desired value can be assigned, and operating parameters that influence these operating values. In other words: in the case of the process space of a printing machine for a printing material web, there are low-dimensional, typically two- or three-dimensional hypersurfaces or hyperplanes in the process space whose position is determined by a specific combination of operating parameters. This fact simplifies the procedures in the process space considerably.
It is accordingly an object of the invention to provide a method of monitoring processes, in particular a printing process, of a web-processing printing machine and an associated apparatus for implementing the method, which overcome the above-mentioned disadvantages of the heretofore-known methods and devices of this general type and which allow the machine operator to make a simple analysis of the actual values of specific operating values and helps avoid operating the machine in a region of critical operating values and operating parameters.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for monitoring processes of a web-processing printing machine, the method includes the steps of:
identifying process variables in a process space as operating values including at least a web tension and a web speed;
carrying out a measurement of actual values of the operating values;
presetting and/or measuring actual values of at least one operating parameter that influences the operating values;
assessing the operating values in dependence on the at least one operating parameter; and
generating a map of the process space by allocating at least a subset of points of the process space to at least two classes representing a measure of a risk of an operating state of the web-processing printing machine.
In other words, the method according to the invention of monitoring processes, in particular the printing process, in a web-processing printing machine, process variables being identified in a process space as operating values, which include at least the web tension and the web speed, a measurement of actual values of the operating values being carried out, a predefinition or a measurement of actual values of at least one operating parameter that influences these operating values being performed and operating values being assessed as a function of the operating parameters, is distinguished by the fact that a map of the process space is generated, an allocation of at least one subset of points of the process space to at least two classes being performed, which represents a measure of the risk of the operating state of the printing machine. In other words, it is distinguished by the fact that there is a map of at least one subset of the process space, typically of the subspace of the operating values or a process space of the operating values as a function of the operating parameters, which subjects the possible operating values to a classification with at least two classes. The process space is formed by the value set of all process variables, a subset of the process variables being referred to or identified as operating values if their special significance for the process has been detected or realized. For example, these are process variables which have to be varied actively or monitored by the machine operator during operation, such as typically the web speed and the web tension. An assessment of operating values can be carried out through the use of simple functional relationship using numerical values from a value set. The group of operating parameters in this case includes printing material characteristics, the time since the last web cut, the time since the last rubber blanket cleaning, parameters of the dryer, the rate of printing material defects on the running reel and the like.
In other words, the process space is the set of all possible operating states which are characterized by process variables, so-called operating values and operating parameters, that is to say the set of all possible combinations of operating values and operating parameters. In other words: the process space is covered by the operating values and the operating parameters. Here, the operating values form a process subspace. A hyperplane or hypersurface in the process space, which is covered i.e. defined by at least two process variables from the set of operating values with the operating parameters fixed, is therefore typically an affine subspace of the entire process space and is also designated a process space of the operating values as a function of the operating parameters.
A map in the process space is therefore understood to mean a projection of at least a subset of the points in the process space into the set of real numbers. The subset of points in the process space will preferably be the process subspace or a process space of the operating values as a function of the operating parameters and the value set will include only a small subset of the real numbers, which has at least two elements. The projection has the meaning of classifying a numerical value for the risk assessment relating to a point in the process space, and will therefore also be designated the risk classification.
The method according to the invention for process monitoring of a printing machine with a map of at least a subset of the process space makes it possible in a simple manner for the machine operator to be given a measure of the risk level, that is to say in particular the probability or for an interval of probabilities of a web break. Therefore, not only is the information about the current actual values of the operating values in the process space supplied, but at the same time information about the environment of these operating values in the process space is made available. Taking this knowledge into account for the monitoring, control and/or regulation of the printing machine can lead to a reduction in the risk of a failure or of the occurrence of nonproductive time.
Provision is made for the accuracy of the map of the process space to be increased through the information obtained through the use of ongoing measurements and their further processing. With an increasing number of measurements, be it on all machines in a series or only on a specific available machine the intention is therefore for the knowledge of the map to be refined. The results of the measurements on other machines in a series can, for example, be used for a specific machine in this series, by corresponding data being imparted to the machine control unit, be it at the time of delivery or be it through the use of transmission. In general, functional values at points in the process space are obtained through the use of test runs and, to an increasing extent, through the use of production runs. Typically, initially statistically distributed points will be concerned, and then areas in the process space will be considered, in which the functional values change considerably.
For the purpose of creating the map or its refinement, interpolations of the functional values of the assessment or classification between measured points in the process space can advantageously be performed. Alternatively or additionally, the increase in the accuracy or the refinement of the knowledge of the map can also be carried out by calculating functional values or classifications by using fuzzy logic with suitable fuzzy sets and fuzzy rules. In an advantageous development of the invention a neural network is used for the further processing of the information obtained through the use of ongoing measurements.
Furthermore, the method according to the invention for process monitoring of a printing machine for a printing material web can advantageously include a predefinition of desired values for the operating values which include at least the web tension and the web speed.
In order to avoid operating the web-processing printing machine with operating values and/or operating parameters which are affected by risk, the change from an actual value to a desired value of the operating values is carried out along a suitable route in the process space, which avoids points in the process space in a specific class whose membership represents a measure of the risk.
An apparatus according to the invention for implementing such a method for process monitoring of a printing machine for a printing material web includes at least one diagnostic apparatus, an input unit, a machine control unit and is distinguished by the fact that a cartography unit provides a map of the process space of the operating values as a function of the operating parameters. For the machine operator, a display apparatus is provided, so that a simple and convenient visualization of the hypersurface in the process space covered by the operating values can be carried out. In an advantageous development of the invention, a navigation unit is provided in order to determine a route in the process space, the navigation unit calculating or carrying out a change of at least one operating value from an actual value to a desired value while avoiding points in the process space.
Such a method according to the invention and such an apparatus according to the invention can particularly advantageously be implemented in a printing machine, in particular a web-fed rotary printing machine or offset printing machine, for a printing material web. In addition to the avoidance of certain risks through the use of specific operating values and operating parameters in the process space, the knowledge of the process space can also be used to optimize quality parameters. Optimal operation with minimized risk can be carried out in advance, at least in a local region of the process space.
With the objects of the invention in view there is also provided, an apparatus for monitoring processes in a web-processing printing machine, including:
an input unit;
a machine control unit connected to the input unit;
a cartography unit connected to the machine control unit;
at least one diagnostic apparatus connected to the cartography unit;
a display apparatus for a machine operator, the display apparatus being connected to the cartography unit; and
the input unit, the machine control unit, the cartography unit, the at least one diagnostic apparatus, and the display apparatus being configured to identify process variables in a process space as operating values including at least a web tension and a web speed, carry out a measurement of actual values of the operating values, perform a step selected from the group of consisting of presetting actual values of at least one operating parameter that influences the operating values and measuring actual values of at least one operating parameter that influences the operating values, assess the operating values as a function of the at least one operating parameter, and generate a map of the process space by allocating at least a subset of points of the process space to at least two classes representing a measure of a risk of an operating state of the web-processing printing machine.
According to another feature of the invention, a navigation unit is connected to the cartography unit, the navigation unit being configured to be provided with desired values for the operating values, and to change an actual value of at least one of the operating values to a desired value of the at least one of the operating values by changing the at least one of the operating values along a given route in the process space such that points in at least one of the at least two classes are avoided.
With the objects of the invention in view there is also provided a printing machine configuration, including:
a web-processing printing machine;
an apparatus for monitoring processes in the web-processing printing machine having an input unit, a machine control unit, a cartography unit, at least one diagnostic apparatus, and a display apparatus; and
the apparatus for monitoring being configured to identify process variables in a process space as operating values including at least a web tension and a web speed, carry out a measurement of actual values of the operating values, perform a step selected from the group of consisting of presetting actual values of at least one operating parameter that influences the operating values and measuring actual values of at least one operating parameter that influences the operating values, assess the operating values as a function of the at least one operating parameter, and generate a map of the process space by allocating at least a subset of points of the process space to at least two classes representing a measure of a risk of an operating state of the web-processing printing machine.
According to a further feature of the invention, the web-processing printing machine is a web-fed rotary printing machine.
According to yet a further feature of the invention, the web-processing printing machine is an offset printing machine.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and apparatus for monitoring processes in a web-processing printing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.